Thorium Brotherhood can be obtained in approximately 15 minutes by a level 80+ toon.
Go to the AH and buy whatever is the cheapest of
Blood of The Mountain
until you have 20 items total (assuming you are at 0 rep Neutral)
Then go to the Grim Guzzler (the pub inside BRD) - turn in items there and bang insta-exalted with Thorium Brotherhood.....no achievement, no real rewards except for some old patterns, but it's one more rep towards the rep achievements :D